Polypropylene thermoplastic elastomer compositions having improved processing properties and physical property balance

ABSTRACT

Thermoplastic elastomer compositions having improved processabillity while maintaining good physical properties are prepared from a mixture of olefinic rubber and a polypropylene composition having a melt flow rate in the range of from about 0.5 to about 5 dg/min. and a molecular weight distribution Mw/Mn of greater than 5.5 up to about 20. The rubber component of the mixture may be at least partially cured by dynamic vulcanization.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to thermoplastic elastomercompositions comprising a blend of polypropylene polymeric and at leastpartially cured or non-cured elastomer having both improvedprocessability and good physical properties.

2. Description of the Prior Art

A thermoplastic elastomer is generally defined as a polymer or blend ofpolymers that can be processed and recycled in the same way as aconventional thermoplastic material, yet has properties and performancesimilar to that of vulcanized rubber at service temperatures. Blends oralloys of plastic and elastomeric rubber have become increasinglyimportant in the production of high performance thermoplasticelastomers, particularly for the replacement of thermoset rubber invarious applications.

Polymer blends which have a combination of both thermoplastic andelastic properties are generally obtained by combining a thermoplasticpolymer with an elastomeric composition in a way such that the elastomeris intimately and uniformly dispersed as a discrete particulate phasewithin a continuous phase of the thermoplastic. Early work withvulcanized compositions is found in U.S. Pat. No. 3,037.954, whichdiscloses static vulcanization as well as the technique of dynamicvulcanization wherein a vulcanizable elastomer is dispersed into aresinous thermoplastic polymer and the elastomer is cured whilecontinuously mixing and shearing the polymer blend. The resultingcomposition is a microgel dispersion of cured elastomer, such as EPDMrubber, butyl rubber, chlorinated butyl rubber, polybutadiene orpolyisoprene in an uncured matrix of thermoplastic polymer such aspolypropylene.

Depending on the ultimate application, such thermoplastic elastomer(TPE) compositions may comprise one or a mixture of thermoplasticmaterials such as propylene homopolymers and propylene copolymers andlike thermoplastics used in combination with one or a mixture of curedor non-cured elastomers such as ethylene/propylene rubber, EPDM rubber,diolefin rubber, butyl rubber or similar elastomers. TPE compositionsmay also be prepared where the thermoplastic material used also includesan engineering resin having good high temperature properties, such as apolyamide or a polyester used in combination with a cured or non-curedelastomer. Examples of such TPE compositions and methods of processingsuch compositions, including methods of dynamic vulcanization, may befound in U.S. Pat. Nos. 4,130,534: 4,130,535; 4,594,390; 5,177,147; and5,290,886, as well as in WO 92/02582.

TPE compositions are normally melt processed using conventionalthermoplastic molding equipment such as by injection molding,compression molding. extrusion, blow molding or other thermoformingtechniques. In such TPE compositions, the presence of the elastomericcomponent does not necessarily improve the processability of thecomposition. In fact, where the elastomeric component is partially orfully cured (cross-linked) in situ during the mixing of the TPE polymercomponents (dynamically vulcanized), or where a dynamically vulcanizedTPE composition is further processed, there are heavier demands placedupon processing machinery as compared with the processing of athermoplastic composition which is free of cured elastomer.Polypropylenes normally used as a thermoplastic component in TPEcompositions are conventional Ziegler/Natta catalyzed crystallinepolymers having a melt flow rate in the range of about 0.7 to 5 dg/min.and a molecular weight distribution (Mw/Mn) of from about 3 to about 4.However, TPE compositions containing these materials are difficult toprocess.

Conventional methods for improving processability or flow in TPEcompositions containing polypropylene involve either a reduction in thecure state where the TPE is vulcanized, the use of a polypropylenecomponent having a relatively low molecular weight (and thus arelatively high melt flow rate) and the addition of high levels ofdiluent processing oil to the composition. Unfortunately, while each ofthese techniques do provide some improvement in processability, apenalty is paid in terms of a diminishment in certain physicalproperties of the composition resulting in lower mechanical properties,e.g., tensile strength, elongation, toughness, modulus and heatdistortion temperature. Elasticity as measured by tension set andcompression set may also be compromised.

SUMMARY OF THE INVENTION

The present invention provides a thermoplastic elastomer compositioncomprising a mixture of a polypropylene polymer composition having amelt flow rate in the range of from about 0.5 to about 5 dg/min and amolecular weight distribution Mw/Mn of greater than 5.5 up to about 20;and an olefinic rubber, wherein said olefinic rubber is present in saidcomposition at a level of about 10 to 90 wt % based on the total polymercontent of said composition.

The invention is based on the discovery that the utilization ofpolypropylene polymer composition having melt flow rate (MFR) andmolecular weight distribution (MWD) values within the above-describedparameters gives rise to thermoplastic elastomer compositions (TPEs),including dynamically vulcanized compositions (DVAs), which are moreprocessable than TPEs containing conventional polypropylenes having anMFR in the range of 0.7 to 5 and MWD of about 3 to 4. Because of thisimproved processability, conventional techniques for improvingprocessability which detract from physical properties of thecomposition, e.g., inclusion of high levels of processing oil or use ofhigh MFR polypropylene as the polypropylene component of thecomposition, can be avoided.

DETAILED DESCRIPTION OF THE INVENTION

Following is a description of the various ingredients which may be usedto formulate the TPE compositions of this invention.

Polypropylene Composition

Polypropylene compositions suitable for use in the present inventionhave a melt flow rate (MFR) from about 0.5 to about 5 dg/min., morepreferably from about 0.5 to 4 dg/min., and a molecular weightdistribution of greater than 5.5 up to about 20, more preferably fromabout 6 to about 15. Molecular weight distribution or polydispersity, isdefined as the weight average molecular weight (Mw) divided by thenumber average molecular weight (Mn) of the polypropylene composition.Mw and Mn of the polypropylene may be determined either using GelPermeation Chromatography (GPC) or by rheology as described in Zeichneret al. “A Comprehensive Evaluation of Polypropylene Melt Rheology,”Proc. 2^(nd) World Congress, Chem. Eng., Vol. 6, pp. 333-337 (1981).Polypropylenes having MFR values within the above parameters as measuredby either GPC or rheology are suitable for use in this invention. MFR isa measure of the ability of the polymer to flow and is reported asdg/min. MFR is determined in accordance with ASTM D 1238 (condition L).Polypropylenes suitable for use herein may be made using conventionalZiegler Natta, metallocene or mixed metallocene catalysts byconventional solution or gas phase reactor polymerization processes.Because it is difficult to adjust polymerization conditions in a singlereactor to produce polypropylene having both an MFR in the 0.5 to 5dg/min. range and an average MWD of greater than 5.5 up to 20, thepolypropylene is more readily prepared by blending at least twodifferent grades of polypropylene, one having an MFR of less than 0.5dg/min. and at least one other having an MFR greater than 3 dg/min.Alternatively, polypropylene compositions meeting the above parametersmay be prepared from a mixture of three polypropylenes, one having anMFR less than 1 dg/min., a second having an MFR greater than 1 dg/min.and a third having an MFR greater than 4 dg/min. These mixtures may beprepared by combining polypropylenes prepared in separate reactors underdiffering polymerization conditions or by sequential polymerization ofmonomer in at least two separate reactor zones wherein differingpolymerization conditions in each zone favor the production ofpolypropylene having different MFR and MWD properties.

Metallocene catalysts which may be used to polymerize polypropylenesused in this invention are one or more compounds represented by theformula Cp_(m) M_(n) X_(q) wherein Cp is a cyclopentadienyl ring whichmay be substituted, or derivative thereof which may be substituted, M isa Group 4, 5, or 6 transition metal, for example, titanium, zirconium,hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten.R is a hydrocarbyl group or hydrocarboxy group having from one to 20carbon atoms, X is a halogen, and m=1-3, n=0-3, q=0-3, and the sum ofm+n+q is equal to the oxidation state of the transition metal.

Methods for making and using matallocenes in polymerization reactionsare very well known in the art. For example, metallocenes are detailedin U.S. Pat. Nos. 4,530,914; 4,549,199; 4,769,910; 4,808,561; 4,871,705;4,933,403: 4,937,299; 5,017,714; 5,026,798; 5,057,475; 5,190,867;5,278,119; 5,304,614; 5,324,800; 5,350,723; and 5,391,790, each fullyincorporated herein by reference.

The Ziegler-Natta catalysts useful in the preparation of polypropylenesof the present invention may be solid titanium supported catalystsystems such as described in U.S. Pat. No. 5,159,021. Briefly, theZiegler-Natta catalyst can be obtained by: (1) suspending a dialkoxymagnesium compound in an aromatic hydrocarbon that is liquid at ambienttemperatures; (2) contacting the dialkoxy magnesium-hydrocarboncomposition with a titanium halide and with a diester of an aromaticdicarbocylic acid: and (3) contacting the resulting functionalizeddialkoxy magnesium-hydrocarbon composition of step (2) with additionaltitanium halide.

The Ziegler-Natta co-catalyst is preferably an organoaluminum compoundthat is halogen free. Suitable halogen free organoaluminum compoundsare, in particular, branched unsubstituted alkylaluminum compounds ofthe formula AIR where R denotes an alkyl radical having 1 to 10 carbonatoms, such as for example, trimethylaluminum, triethylaluminum,triisobutylaluminum and tridiisobutylaluminum. Additional compounds thatare suitable for use as a co-catalyst are readily available and amplydisclosed in the prior art, including U.S. Pat. No. 4,990,477, which isincorporated herein by reference. The same or different Ziegler-Nattacatalyst(s) can be used in both the initial and subsequentpolymerization steps.

Electron donors are typically used in two ways in the formation ofZiegler-Natta catalysts and catalyst systems. An internal electron donormay be used in the information reaction of the catalyst as thetransition metal halide is reacted with the metal hydride or metalalkyl. Examples of internal electron donors include amines, amides,ethers, esters, aromatic esters, ketones, nitriles, phosphines,stilbenes, arsines, phosphoramides, thioethers, thioesters, aldehydes,alcoholates, and salts of organic acids. In conjunction with an internaldonor, an external electron donor is also used in combination with acatalyst. External electron donors affect the level of stereoregularityand MFR in polymerization reactions. External electron donor materialsinclude organic silicon compounds, e.g., tetraethoxysilane andcicyclopentydimethoxysilane. Internal and external type electron donorsare described, for example, in U.S. Pat. No. 4,535,068, which isincorporated herein by reference. The use of organic silicon compoundsas external electron donors are described, for example, in U.S. Pat.Nos. 4,218,339; 4,395,360; 4,328,122; and 4,473,660, all of which areincorporated herein by reference.

Polypropylenes suitable for use herein are at least partiallycrystalline materials having an Mn in the range of about 10,000 to250,000 and include polypropylene homopolymers as well as reactorcopolymers of propylene which can contain about up to about 20 wt % ofethylene or an alphaolefin comonomer of 4 to 16 carbon atoms or mixturesthereof. Thus, the term “polypropylene” as used herein intended to coverboth homopolymers and copolymers.

The composition of the invention may also contain one or more otherthermoplastic polymer components in addition to the polypropylenecomponent described above. These include other monoolefin polymers orcopolymers based on monomers having 2-6 carbon atoms such as ethylene1-butene, isobutylene, 1-pentene and the like.

Additional Thermoplastic Polymers.

In addition to the polypropylene polymer composition and otherpolyolefin components, the composition may also contain one or moreother thermoplastic polymers selected from the group consisting ofpolyamides, polyimides, polyesters, polycarbonates, polysulfones,polylactones, polyacetals, acrylontrile/butadiene/styrene copolymerresins, polyphenylene oxides, ethylene/carbon monoxide copolymers,polyphenylene sulfides, polystyrene, styrene/acrylonitrile copolymerresins, styrene/maleic anhydride copolymer resins, aromatic polyketonesand mixtures thereof.

Suitable thermoplastic polyamides (nylons) comprise crystalline orresinous, high molecular weight solid polymers including copolymers andterpolymers having recurring amide units within the polymer chain.Polyamides may be prepared by polymerization of one or more epsilonlactams such as caprolactam, pyrrolidione, lauryllactam andaminoundecanoic lactam, or amino acid, or by condensation of dibasicacids and diamines. Both fiber-forming and molding grade nylons aresuitable. Examples of such polyamides are polycaprolactam (nylon 6),polylauryllactam (nylon 12), polyhexamethyleneadipamide (nylon-6,6),polyhexamethyleneazelamide (nylon-6,9), polyhexamethylenesebacamide(nylon 6,10), polyhexamethyleneisophthalamide (nylon-6,IP) and thecondensation product of 11-amino-undecanoic acid (nylon 11).Commerically available thermoplastic polyamides may be advantageouslyused in the practice of this invention, with linear crystallinepolyamides having a softening point or melting point between 160°C.-230° C. being preferred.

Suitable thermoplastic polyesters which may be employed include thepolymer reaction products of one or a mixture of alphatic or aromaticpolycarboxylic acids, esters of anhydrides and one or a mixture ofdiols. Examples of satisfactory polyesters include poly(trans-1,4-cyclohexylene C₂₋₆ alkane discarbaoxylates such as poly(trans-1,4-cyclohexylene succinate) and poly (trans-1,4 cyclohexyleneadipate);poly (cis or trans-1,4-cyclohexanedimethylene)alkanedicarboxylates such as poly (cis 1,4-cyclohexane-dimethylene)oxylate and poly (cis1,4-cyclohexanedimethylene) succinate, poly (C₂₋₄alkylene terephthalates) such as polyethyleneterephthalate andpolytetramethyleneterephthalate, poly (C₂₋₄ alkylene isophthalates) suchas poolyethyleneisophthalate and polyltetramethylene isophthalate andlike materials. Preferred polyesters are derived from aromaticdicarboxylic acids such as naphthalenic or phthalic acids and C₂ to C₄diols, such as pollyethyilene terephthalate and polybutyleneterephthalate. Preferred pollyessters will have a melting point in therange of 160° to 260°.

Poly(phenylene ether) (PPE) thermoplastic engineering resins which maybe used in accordance with this invention are well known, commerciallyavailable materials produced by the oxidative coupling polymerization ofalkyl substituted phenols. They are generally linear polymers having aglass transition temperature in the range of about 190° C. to 235° C.Examples of preferred PPE polymers include poly(2,6-dialkyl-1,4phenylene ethers) such as poly(2,6 dimethyl-1,4-phenylenether), poly2-methyl-6-ethyl-1,4 phenylene ether), poly-(2,6-dipropyl-1,4-phenyleneether) and poly (2-ethyl-6-propyl-1,4-phenylene ether). These polymers,their method of preparation and blends with polystyrene are furtherdescribed in U.S. Pat. No. 3,383,435, the complete disclosure of whichis incorporated herein by reference.

Other thermoplastic resins which may be used include the polycarbonateanalogs of the polyesters described above such as segmented poly(ethercophthalates); polycaprolactone polymers; styrene resins such ascopolymers of styrene with less than 50 mole % of acrylonitrile (SAN)and resinous copolymers of styrene, acrylonitrile and butadiene (ABS);sulfone polymers such as polyphenylsulfone, and like engineering resinsas are known in the art.

Olefinic Rubber

Suitable rubbery materials which may be used include monoolefincopolymeric rubbers, isobutylene copolymers and diolefin rubbers, aswell as mixtures thereof.

Suitable monoolefin copolymer rubbers comprise non-polar, essentiallynon-crystalline, rubbery copolymers of two or more alpha-monoolefins,preferably copolymerized with at least one polyene, usually a diene.Saturated monoolefin copolymer rubber, for example, ethylene-propylenecopolymer rubber (EPM) can be used. However, unsaturated monoolefinrubber such as EPDM rubber is more suitable. EPDM is a terpolymer ofethylene, propylene and a non-conjugated diene. Satisfactorynon-conjugated dienes include 5-ethylidene-2-norbornene (ENB);vinylnorbornene (VNB); 1,4-hexadiene; 5-methylene-2-norbornene (MNB);1,6-octadiene; 5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene;1,3-cyclopentadiene; 1,4-cyclohexadiene; dicyclopentadiene (DCPD); andthe like.

Butyl rubbers are also useful in the compositions of the invention. Asused in the specification and claims, the term “butyl rubber” includescopolymers of an isoolefin and a conjugated diene, terpolymers of anisoolefin, a conjugated diene and a divinyl aromatic monomer, and thehalogenated derivatives of such copolymers and terpolymers. The usefulbutyl rubber copolymers comprise a major portion of isoolefin and aminor amount, usually less than 30 wt %, of a conjugated diene, and arepreferably halogenated, e.g., brominated, to facilitate curing. Thepreferred copolymers comprise about 85-99.5 wt % of a C₄₋₇ isoolefinsuch as isobutylene and about 15.05 wt % of a multiolefin of 4-14 carbonatoms, such as isoprene, butadiene, dimethyl butadiene and piperylene.Commercial butyl rubber, useful in the invention, is a copolymer ofisobutylene and minor amounts of isoprene. Other butyl co- andterpolymer rubbers are illustrated by the description in U.S. Pat. No.4,916,180, which is fully incorporated herein by this reference

Another suitable copolymer within the scope of the olefinic rubber ofthe present invention is a copolymer of a C₄₋₇ isomonoolefin and aparaalkylstyrene, and preferably a halogenated derivative thereof. Theamount of halogen in the copolymer, predominantly present as benzylichalogen, is from about 0.1 to about 10 wt. %. A preferred example is thebrominated copolymer of isobutylene and paramethylstyrene. Thesecopolymers are more fully described in U.S. Pat. No. 5,162,445, which isfully incorporated herein by reference.

Another olefinic rubber class which may be used are diolefins such aspolybutadiene as well as elastomeric random copolymers of butadiene withless than 50 wt % of styrene or acrylonitrile. Other suitable diolefinmaterials include natural rubber or synthetic polyisoprene. Mixturescomprising two or more of the olefinic rubbers may also be used.Depending upon the desired application, the amount of olefinic rubberpresent in the composition may range from about 10 to about 90 wt % ofthe total polymer content of the composition. In most applications andparticularly where the rubber component is dynamically vulcanized, therubber component will constitute less than 70 wt %, more preferably lessthan 50 wt %, and most preferably about 10-40 wt % of the total polymercontent of the composition.

Additives

The compositions of the invention may include plasticizers, curativesand may also include reinforcing and non-reinforcing fillers,antioxidants, stabilizers, rubber, processing oil, plasticizers,extender oils, lubricants, antiblocking agents, anti-static agents,waxes, foaming agents, pigments, flame retardants and other processingaids known in the rubber compounding art. Such additives can comprise upto about 50 wt % of the total composition. Fillers and extenders whichcan be utilized include conventional inorganics such as calciumcarbonate, clays, silica, talc titanium dioxide, carbon black and thelike. The rubber processing oils generally are paraffinic, naphthenic oraromatic oils derived from petroleum fractions, but are preferablyparaffinic. The type will be that ordinarily used in conjunction withthe specific rubber or rubbers present in the composition, and thequantity based on the total rubber content may range from zero up to1-200 parts by weight per hundred rubber (phr). Plasticizers such astrimellitate esters or aliphatic esters may also be present in thecomposition.

Processing

The olefin rubber component of the thermoplastic elastomer is generallypresent as small, i.e., micro-size particles within a continuous plasticmatrix, although a co-continuous morphology or a phase inversion is alsopossible depending on the amount of rubber relative to plastic, and thecure system or degree of cure of the rubber. The rubber may be at leastpartially crosslinked, and preferably is completely or fullycrosslinked. The partial or complete crosslinking can be achieved byadding an appropriate rubber curative to the blend of thermoplasticpolymer and rubber and vulcanizing the rubber to the desired degreeunder conventional vulcanizing conditions. However, it is preferred thatthe rubber be crosslinked by the process of dynamic vulcanization. Asused in the specification and claims, the term “dynamic vulcanziation”means a vulcanization or curing process for a rubber contained in athermoplastic elastomer composition, wherein the rubber is vulcanizedunder conditions of high shear at a temperature above the melting pointof the component thermoplastic. The rubber is thus simultaneouslycrosslinked and dispersed as fine particles within the matrixthermoplastic, although as noted above other morphologies may alsoexist. Dynamic vulcanization is effected by mixing the thermoplasticelastomer components at elevated temperature in conventional mixingequipment such as roll mills, Banbury mixers, Brabender mixers,continuous mixers, mixing extruders and the like. The uniquecharacteristic of dynamically cured compositions is that,notwithstanding the fact that the rubber component is partially or fullycured, the compositions can be processed and reprocessed by conventionalplastic processing techniques such as extrusion, injection molding, blowmolding, and compression molding. Scrap or flashing can be salvaged andreprocessed.

Those ordinarily skilled in the art will appreciate the appropriatequantities, types of cure systems, and vulcanization conditions requiredto carry out the vulcanization of the rubber. The rubber can bevulcanized using varying amounts of curative, varying temperatures andvarying time of cure in order to obtain the optimum crosslinkingdesired. Any known cure system for the rubber can be used, so long as itis suitable under the vulcanization conditions with the specificolefinic rubber or combination of rubbers being used and with thethermoplastic component. These curatives include sulfur, sulfur donors,metal oxides, resin systems, peroxide-based systems, hydrosilationcuratives containing platinum or peroxide catalysts, and the like, bothwith and without accelerators and co-agents. Such cure systems are wellknown in the art and literature of vulcanization of elastomers.

The terms “full vulcanized” and “completely vulcanized” mean that therubber component to be vulcanized has been cured to a state in which theelastomeric properties of the crosslinked rubber are similar to those ofthe rubber in its conventional vulcanized state, apart from thethermoplastic elastomer composition. The degree of cure can be describedin terms of gel content or, conversely, extractable components.Alternatively the degree of cure may be expressed in terms of crosslinkdensity. All of these descriptions are well known in the art as forexample disclosed in U.S. Pat. Nos. 5,100,947 and 5,157,081, both ofwhich are fully incorporated herein by reference.

Melt processing temperatures will generally range from above the meltingpoint of the highest melting polymer present in the TPE composition upto about 300° C. Preferred processing temperatures will range from about140° C. up to 250° C., more preferably from about 150° C. up to 225° C.

The following examples are illustrative of the invention.

A number of dynamically vulcanized compositions as illustrated in TablesII, IV, V, VI, and VII were prepared by melt mixing a mixture ofolefinic rubber, propylene polymer, processing oil, curatives andadditives as shown in these tables and curing the composition in situ ina high shear mixing device at an elevated temperature of about 200° C.Table I identifies the various propylene polymers utilized in theseexamples. Polypropylenes identified as PP-1 through PP-8 and PP-13through PP-16 have MWD and MFR values which are outside the greater than5.5-20 and 0.5 to 5 dg/min. range respectively, while PP-9 through PP-12have values within these ranges. Most of these polypropylenes arecommercially available materials except as follows:

PP-9 is a polypropylene mixture made in a three-stage reactor andcomprising 45 wt % of a 34 dg/min. MFR polypropylene, 33 wt % of a 1.0dg/min. polypropylene and 22 wt % of a 0.6 dg/min. MFR polypropylene.

PP-10 is a polypropylene mixture made by blending 50 wt % of a 400dg/min. MFR polypropylene and 50 wt % of a 0.2 dg/min. MFRpolypropylene.

PP-11 is a polypropylene mixture made by blending 23.5 wt % of a 400dg/min. MFR polypropylene, 17 wt % of a 57 dg/min. MFR polypropylene and59.5 wt % of a 0.33 dg/min. MFR polypropylene.

Formulations identified by “c” numbers in the table headings are controlformulations outside the scope of the invention; formulations identifiedas EX-1 through EX-10 are within the scope of the invention.

Physical and mechanical properties of each of the cured compositionswere measured by the procedures shown in Table VIII.

Physical and mechanical properties of the various control vulcanizatesand vulcanizates of the invention are compared in Tables III-VII. Inthose cases where the controls exhibit similar or better spiral flow,e.g., C-10, C-12, C-15, C-30 and C-32, the data show that good spiralflow is achieved at the expense of one or more mechanical propertiessuch as melt strength (extensional viscosity), tensile strength,elongation, extrusion surface roughness and shear viscosity as measuredby automatic capillary rheometer (ACR).

Thus, the use of broad MWD polypropylenes as components of DVAcompositions in accordance with this invention provide compositionshaving excellent processability while still maintaining an excellentbalance of engineering properties such as tensile strength, meltstrength, modulus and elongation.

While preferred embodiments of the invention have been disclosed indetail, it should be understood by those skilled in the art that variousother modifications may be made to the illustrated embodiments withoutdeparting from the scope and spirit of the invention as described in thespecification and defined in the appended claims.

TABLE I Characterization of Various Polypropylenes Poly- MWD propyleneMw Mn MWD Rheo- MFR Number Catalyst g/mole g/mole GPC logy dg/min PP-1Ziegler-Natta 588,150 119,100 4.93 5.0 0.8 PP-2 Ziegler-Natta 552,980143,560 3.85 4.0 0.7 PP-3 metallocene 186,888 102,203 1.83 2.0 10 PP-4Ziegler-Natta 196,584  39,742 4.95 5.0 11.4 PP-5 Ziegler-Natta 158,785 49,524 3.21 4.2 20 PP-6 metallocene 282,614  80,335 3.52 4.1 2.9 PP-7Ziegler-Natta 213,904  34,520 6.19 6.0 5.5 PP-8 Ziegler-Natta 387,927108,691 3.56 4.6 1.88 PP-9 Ziegler-Natta 338,627  40,131 8.44 6.94 3.6PP-10 Ziegler-Natta 309,075  25,053 12.34 10.7 2.2 PP-11 Ziegler-Natta —— — 10.2 1.6 PP-12 Ziegler-Natta 591,600  58,000 10.2 9.3 0.9 PP-13Ziegler-Natta 382,800 103,460 3.7 3.5 4 PP-14 Ziegler-Natta 379,100 7,350 5.2 4.8 1.8 PP-15 Ziegler-Natta 452,700 133,140 3.4 3.9 0.43PP-16 Ziegler-Natta 332,600  72,300 4.6 4.7 1.7

TABLE II EFFECT OF NEW BROAD MWD POLYPROPYLENES ON PROPERTIES OF DVASExample C-1 C-2 C-3 C-4 C-5 C-6 C-7 C-8 C-9 EX-1 EX-2 C-10 TPEComposition (Parts by Weight) EPDM1, C2 = 55%, ENB = 5%, ML(1 + 4) = 90100 100 100 100 100 100 100 100 100 100 100 0 EPDM 2, C2 = 60%, ENB =4.5%, ML(1 + 4) = 63 0 0 0 0 0 0 0 0 0 0 0 175 2 ZnO/1.5 SnCl2 BLEND/(5Wax in Example C10) 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 8.5 22.6Black Concentrate/12 clay 0 0 0 0 0 0 0 0 0 0 0 32.6 SP-1046 phenolicresin 1.5 5 5 5 5 5 5 5 5 5 5 5.3 SUNPAR 150 M 107 107 107 107 107 107107 107 107 107 107 90 PP-2 50 50 50 0 0 0 0 0 0 0 0 0 PP-3 0 0 0 50 0 00 0 0 0 0 0 PP-4 0 0 0 0 50 0 0 0 0 0 0 0 PP-5 0 0 0 0 0 50 0 0 0 0 0 0PP-6 0 0 0 0 0 0 50 0 0 0 0 0 PP-8 0 0 0 0 0 0 0 50 0 0 0 0 PP-7 0 0 0 00 0 0 0 50 0 0 0 PP-9 0 0 0 0 0 0 0 0 0 50 0 0 PP-10 0 0 0 0 0 0 0 0 0 050 0 PP-13 0 0 0 0 0 0 0 0 0 0 0 63 TOTAL (Parts by Weight) 262 265.5265.5 265.5 265.5 265.5 265.5 265.5 265.5 265.5 265.5 374.4 Cure StatePart. Full Full Full Full Full Full Full Full Full Full Cure Full CureCure Cure Cure Cure Cure Cure Cure Cure Cure Cure

TABLE III Effect of New Broad MWD Polypropylenes on Properties of DVAsExample C-1 C-2 C-3 C-4 C-5 C-6 Polypropylene Identification Number PP-2PP-2 PP-2 PP-3 PP-4 PP-6 Specific Gravity 0.876 0.876 0.883 0.882 0.8760.877 ACR, Viscosity at 190 C. (poise) 1043 2112 — 1359 890 1300 ACR,Viscosity at 204 C. (poise) 547 917 753 749 466 804 ACR, Viscosity at210 C. (poise) 480 840 — 1066 404 631 Extensional Viscosity at 190 C.(MPa s) 0.0866 0.155 0.179 0.0753 0.0868 0.0532 Spiral Flow at 400 F. at950 psi (Mold T = 100 F.) (in) 25 21 20 18 27 22 Extrusion SurfaceRoughness, Ra (Microns) 403 678 676 488 191 124 Hardness, (Shore A) 6265 68 59 63 65 Stress at 100% strain, (MPa) 23° C. 3.08 3.78 2.99 2.853.16 3.14 125° C. 0.82 1.33 — 0.80 1.26 1.11 Tensile Strength, (MPa) 23°C. 6.01 8.55 6.19 6.26 7.16 7.48 125° C. 2.21 3.39 1.70 2.32 2.24Elongation at break, (%) 23° C. 466 378 328 344 363 367 125° C. 650 354— 296 290 333 Toughness, (MPa) 23° C. 19.22 19.28 12.62 12.84 15.4315.84 125° C. 8.22 6.51 — 2.69 3.85 3.58 Tension Set, %, 20 15 15 10 1310 Wt. Gain, 24 h at 125 C. (%) 198 124 129 Disintegrated 128 129Example C-7 C-8 C-9 EX-1 EX-2 C-10 Polypropylene Identification NumberPP-6 PP-8 PP-7 PP-9 PP-10 PP-13 Specific Gravity 0.878 0.886 0.878 0.8790.882 0.91 ACR, Viscosity at 190 C. (poise) 1396 — 934 1097 1088 ACR,Viscosity at 204 C. (poise) 730 485 448 631 458 70 ACR, Viscosity at 210C. (poise) 822 — 392 614 463 Extensional Viscosity at 190 C. (MPa s)0.0836 0.141 0.075 0.147 0.17 0.0223 Spiral Flow at 400 F. at 950 psi(Mold T = 100 F.) (in) 20 25 25 27 29 42 Extrusion Surface Roughness, Ra(Microns) 247 488 232 278 266 60 Hardness, (Shore A) 62 70 62 63 68 62Stress at 100% strain, (MPa) 23° C. 3.06 2.89 3.03 3.48 3.46 2.34 125°C. 0.99 — 1.08 1.27 1.16 0.54 Tensile Strength, (MPa) 23° C. 8.47 6.476.56 6.69 6.47 4.52 125° C. 2.61 — 2.23 2.40 2.32 1.10 Elongation atbreak, (%) 23° C. 420 330 357 352 365 340 125° C. 331 — 310 322 357 415Toughness, (MPa) 23° C. 19.74 12.59 14.11 15.06 14.79 — 125° C. 4.52 —3.97 4.52 4.97 — Tension Set, %, 10 11 13 15 15 11 Wt. Gain, 24 h at 125C. (%) 214 123 135 441 145 115 Example C-10 uses impact PP copolymer andhigh level of oil - Approach improves flow but detract from engineeringproperties, lower tensiles especially at elevated temperatures and verylow melt strength

TABLE IV Effect of Broad MWD Polypropylenes on Physical And PerformanceProperties Example C-11 C-12 C-13 C-14 C-15 C-16 Ex-3 Ex-4 Ex-5 TPEComposition (Parts by Weight) ZnO/SnCl2 blend 2/1.26 2/1.26 2/1.262/1.26 2/1.26 2/1.26 2/1.26 2/1.26 2/1.26 EPDM 3, C2 = 66%, ENB = 3.8%,ML(1 + 4) = 51 175 175 175 175 175 175 175 175 175 ICECAP K CLAY 10 1010 10 10 10 10 10 10 SUNOLITE WAX 5 5 5 5 5 5 5 5 5 SP-1045, phenolicresin 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 SUNPAR 150 M 55 81 55 55 55 5555 55 55 PP-1, 0.8 MFR 41 0 0 0 0 0 0 0 0 PP-2, 0.7 MFR 0 50 41 41 0 0 00 0 PP-5, 20 MFR 0 0 0 0 41 0 0 0 0 PP-8, 1.9 MFR 0 0 0 0 0 41 0 0 0PP-9, 3.6 MFR 0 0 0 0 0 0 41 0 0 PP-10, 2.2 MFR 0 0 0 0 0 0 0 41 0PP-11, 1.6 MFR 0 0 0 0 0 0 0 0 41 TOTAL (Parts by Weight) 290.5 325.5290.5 290.5 290.5 290.5 290.5 290.5 290.5 POLYPROPYLENE NUMBER PP-1 PP-2PP-2 PP-2 PP-5 PP-8 PP-9 PP-10 PP-11 HARDNESS, (Shore A) 59 56 63 54 5764 61 60 68 Specific gravity 0.901 0.897 0.90 0.90 0.903 0.90 0.8980.901 0.899 Tensile Strength, (psi) 688 909 786 619 559 740 686 753 768Elongation @ Break, (%) 353 382 377 420 323 405 384 431 304 Modulus at100% elongation, (psi) 310 382 350 323 293 305 330 318 596 WT. GAIN, 24h @ 125 C. (%) 129 75 117 110 107 113 108 102 130 ROD DRAW 3.1 4.2 2.43.4 2.3 3.5 2.3 3 — TENSION SET @ 23 C., (%) 13 13 13 9 12 9 9 10 15Compression Set, 22 h @ 100 C. (%) 48 57 46 45 37 46 46 46 — ACRVISCOSITY, @ 190 C. (poise) 907 314 803 — 116 — 481 515 ACR VISCOSITY, @204 C. (poise) 366 132 300 370 105 169 250 225 309 Extrusion SurfaceRating, (Microns) 124 85 118 185 127 121 60 57 127 Spiral Flow, @ 400 F.@ 950 psi (in) 26 33 25 25 33 32 33 34 33 Extensional Viscosity, @ 190C., (MPa s) 0.131 0.079 0.109 0.128 0.0203 0.0729 0.133 0.158 14.5FOAMABILITY CHARACTERISTICS SPECIFIC GRAVITY, FOAMED PROFILE 0.35 — 0.550.4 0.68 0.3 — 0.14 — PROFILE DIAMETER 0.22 — 0.17 0.185 0.113 0.217 —0.332 — TPE Example C-12 - More Oil, more PP: improve flow butdetraction from rubbery behavior. e.g. higher compression set and lowermelting point

TABLE V Effect of MFR and MWD of PP on properties of ‘hard’ TPE gradesInvention Example C-17 C-18 C-19 C-20 Ex-6 Ex-7 C-21 C-22 C-23 TPEComposition (Parts by Weight) EPDM 3, C2 = 66%; ENB = 3.8%; ML(1 + 4) =51 175 175 175 175 175 175 175 175 175 Clay 10 10 10 10 10 10 10 10 10Wax 5 5 5 5 5 5 5 5 5 SP1045 6 6 6 6 6 6 6 6 6 ZnO, 2; SnCl2 1.26 3.263.26 3.26 3.26 3.26 3.26 3.26 3.26 3.26 PP-1, 0.8 MFR, 5.0 MWD 223 223 00 0 0 0 0 0 PP-2, 0.7 MFR, 3.9 MWD 0 0 223 223 0 0 0 0 0 PP-10, 2.2 MFR,10.7 MWD 0 0 0 0 223 0 0 0 0 PP-12, 0.9 MFR, 9.3 MWD 0 0 0 0 0 223 0 0 0PP-14, 1.78 MFR, 4.8 MWD 0 0 0 0 0 0 223 0 0 PP-15, 0.43 MFR, 3.9 MWD 00 0 0 0 0 0 223 0 PP-16, 1.65 MFR, 4.7 MWD 0 0 0 0 0 0 0 0 223 Total(Parts by Weight) 422.26 422.26 422.26 422.26 422.26 422.26 422.26422.26 422.26 Hardness, (Shore D) 38 39 40 40 38 39 37 38 39 TensileStrength, (psi) 2582 2770 2698 2712 2282 2582 2379 2872 2698 Elongationat Break, (%) 551 547 555 541 532 523 555 596 555 Modulus at 100%elongation, (psi) 1299 1334 1310 1334 1489 1479 1212 1347 1321 WT. GAIN,24 h at 125 C. in ASTM Fluid 3, (%) 46 45 48 44 48 51 56 44 45 ACRVISCOSITY at 204 C., (poise) 560 724 883 774 236 688 316 1023 360Extrusion Surface Rating, micron 46 107 39 109 35 105 66 43 39 SpiralFlow, @ 950 psi @ 400 F., (in) 24 23 24 22 38 27 30 21 29 TENSION SET, %39.5 40 39 40 42 42.5 — 40.5 44.5 Compression Set, % 54 56 52 57 59 5854 50 55

TABLE VI TO EVALUATE VARIOUS PP USING BUTYL 268 RUBBER. Example C-24C-25 C-26 Ex-8 Ex-9 C-27 TPE Composition (Parts by Weight) BUTYL 268RUBBER 100 100 100 100 100 100 ICECAP K CLAY 9 9 9 9 9 9 POWDERBLEND(ZnO/SnCl2) 5 5 5 5 5 5 SP-1045 5 5 5 5 5 5 SUNPAR 150 M 100 100100 100 100 100 PP-2, 51S07A 60 0 0 0 0 0 PP-1, D008M 0 60 0 0 0 0 PP-5,FP200F 0 0 60 0 0 0 PP-9, 20045-20-001(PLTD1130) 0 0 0 60 0 0 PP-10,20045-20-003 0 0 0 0 60 0 PP-8, 4782 0 0 0 0 0 60 TOTAL (Parts byWeight) 279 279 279 279 279 279 Hardness, (Shore A) 82 87 82 87 84 84Specific Gravity 0.972 0.972 0.962 0.97 0.974 0.972 Ultimate TensileStrength, (psi) 1115 1349 780 1087 1058 1248 Elongation at Break, (%)441 535 399 494 507 530 Modulus at 100% Elongation, (psi) 669 600 531774 605 758 Processability Characteristics ACR VISCOSITY at 204 C.,(poise) 364 335 74 211 278 200 Extrusion Surface Rating, (Micron) 391909 140 133 232 278 Spiral Flow, at 950 psi at 400 F., (ins) 28 27 45 3933 34 Tension Set, (%) 35 34 37 35 35 37

TABLE VII EFFECT OF BROAD MWD POLYPROPYLENES ON PHYSICAL AND PERFORMANCEPROPERTIES OF TPEa Examples C-28 C-29 C-30 Ex-10 C-32 Composition (Partsby Weight) Oil-extended Rubber Blend (VNB-EPDM, +20 phr clay) 220 220220 220 220 ICECAP K CLAY 22 22 22 22 22 Silicon Hydride 2-2822 (DowCorning) 2 2 2 2 2 Platinum Catalyst, PC 085(0.11%) 3.8 3.8 3.8 3.8 3.8SUNPAR 150 LW 56 56 56 56 56 STABILIZER SLURRY 12 12 12 12 12 PP-2, 0.7MFR 50 0 0 0 0 PP-1, 0.8 MFR 0 50 0 0 0 PP-5, 20 MFR 0 0 50 0 0 PP-9,3.6 MFR 0 0 0 50 0 PP-8, 1.9 MFR 0 0 0 0 50 TOTAL (Parts by Weight)365.8 365.8 365.8 365.8 365.8 HARDNESS, (SHORE A) 69A 68A 62A 66A 66ASPECIFIC GRAVITY 0.951 0.952 0.953 0.954 0.945 TENSILE STRENGTH, (Mpa)6.05 6.25 4.84 5.26 5.53 ELONGATIION AT BREAK, (%) 521 562 454 468 522Modulus at 100% elongation, (MPa) 2.34 2.34 2.19 2.04 2.22 WT. GAIN, %,24 h at 125 C., Repeat 105 115 113 107 110 ROD DRAW 2.1 2.3 2 3 2.5COLOR L 74.91 73.96 75.6 76.11 75.37 COLOR a −1.24 −1.04 −1.17 −1.03−0.91 COLOR b 7.5 6.91 7.37 8.26 8.74 COMPRESSION SET, 22 H AT 100 C.(%) 50 46 47 46 47 TENSION SET, (%) 12 12 11 9 11 Spiral Flow at 950 psiat 400 F. (in) 27 28 31 29 29 Extrusion Surface Rating, (micron) 47 5345 58 49 ACR VISCOSITY, at 204 C. (poise) 320 287 206 326 232EXTENSIONAL VISCOSITY AT 190 C. (MPa s) 0.0586 0.069 0.0369 0.118 0.0629FOAMABILITY Best S.G. 0.96 0.98 — 0.21 0.39 PROFILE DIAMETER, (in) 0.1460.151 — 0.275 0.2 **Cannot Measure

TABLE VIII Test Methods Property Units Procedure Specific Gravity — ASTMD-792 Hardness Shore A or Shore D ASTM D-2240 Tensile Strength MPa orpsi ASTM D-412 Elongation at Break % ASTM D-412 100% Modulus MPa or psiASTM D-412 Compression Set % ASTM D-395 (Method B) Tension Set % ASTMD-412 Weight Gain % ASTM D-471 Extrusion Surface Profilometer micronTPE-0106 ACR Viscosity poise TPE-0137 Extrusion Rod Draw Ratio —TPE-0168 Spiral Flow ins TPE-0032

What is claimed is:
 1. A thermoplastic elastomer composition comprisinga mixture of: a) a polypropylene polymer composition having a melt flowrate in the range of from about 0.5 to about 5 dg/10 min. and amolecular weight distribution Mw/Mn of greater than 5.5 up to about 20;and b) an olefinic rubber, wherein said olefinic rubber is present insaid composition at a level of about 10 to 90 wt % based on the totalpolymer content of said composition.
 2. The composition of claim 1wherein said polypropylene polymer composition has a molecular weightdistribution in the range of about 6 to about
 15. 3. The composition ofclaim 1 wherein said polypropylene polymer composition has a melt flowrate in the range of about 0.5 to about 4 dg/min.
 4. The composition ofclaim 1 wherein said polypropylene polymer composition comprises amixture of at least two polypropylenes, one having a melt flow rate ofless than 0.5 dg/min. and at least one other having a melt flow rategreater than 3 dg/min.
 5. The composition of claim 1 wherein saidpolypropylene polymer composition comprises a mixture of at least threepolypropylenes, one having a melt flow rate less than 0.1 dg/min., asecond having a melt flow rate greater than 1 dg/min. and a third havinga melt flow rate greater than 4 dg/min.
 6. The composition of claim 1wherein said polypropylene polymer composition comprises polypropylenehomopolymer.
 7. The composition of claim 1 wherein said olefinic rubberis selected from the group consisting of ethylene/propylene copolymers.ethylene/propylene/non-conjugated diene terpolymers, isobutylenecopolymers, diolefin polymers and mixture thereof.
 8. The composition ofclaim 1 wherein said olefinic rubber is at least partially crosslinkedby dynamic vulcanization.
 9. The composition of claim 1 which furthercontains an additional thermoplastic polymer component different fromcomponent (a).
 10. The composition of claim 1 which further containsfrom about 1 to 200 parts by weight of rubber processing oil per 100parts by weight of said olefinic rubber.
 11. The composition of claim 1which further contains a curing system for said olefinic rubber.